1. Field of Invention
This invention relates to maps, specifically to a machine and method for obtaining instant distance measurement information from a map.
2. Prior Art
The most conventional method of determining or indicating the distance between two points on a printed map is to first measure or estimate the distance in small units (inches or centimeters) between the two points on the map. Then this distance is multiplied by scale factor on the map to obtain the geographical distance. However, this method does not provide an immediate and accurate report of the geographical distance. It is not practical to use this method when an instant distance measurement is required.
U.S. Pat. No. 5,062,063 to Shimizu; Atsuko and Akishima, (1991) shows a length measuring apparatus which is capable of calculating an actual distance by measuring length on a map and which has a display section to display the actual distance thus calculated. A length measuring apparatus is required for measuring length of a path connecting two points on a map. The length measuring apparatus may be a rolling member which rolls along the path. This method requires a user to carry around various maps, a length measuring device, computer storage, and a display. It takes substantial effort, time and much equipment to obtain a single distance measurement using this method. It is not a convenient method to obtain many distance measurements in a short time in a field location.
U.S. Pat. No. 5,289,167 to Kurosawa; Kazuyuki; Shibutani and Atsushi (1994) shows a display apparatus for processing distance information where scale reduction information of the map and time information is analyzed. It also requires a television circuit for displaying a television image on a display. Heavy equipment must be utilized. This is not suitable for obtaining numerous distance measurements in a field location.
Electronic maps pre-loaded in a computer with display unit are used very often in a moving vehicle for navigational purpose. To obtain a geographical distance, one must first enter the selected locations into a processing computer. The selected locations are entered by typing the addresses on a keyboard, or using an electronic mouse to click on the selected points on the map. It is cumbersome and slow to enter the selected points using these methods. It is also not practical to carry around a keyboard or a mouse in a field location for purpose of entering a selected point on a map into a computer.
3. Objects and Advantages
Accordingly, several objects and advantages of the invention are:
a. Easy method to enter a location in a map to obtain distance measurement. New location is entered through a touch pressure application pen pointing directly at the location on a displayed map through a touch-sensitive screen. PA1 b. Clear indication to the operator of the links measured on the map. A linked line is displayed on the map to indicate the distance measured. PA1 c. Quick clearance of the display and to setup for new measurements. The old link and distance display are immediately cleared from the screen when the operator decides to obtain a new measurement. PA1 d. Provides instant distance measurement from a current position marker to any point on a map.